I see so many people asking this question or just way, WAY overpurchasing RAM so I thought I'd post this. There is a very simple & quick way of seeing if you actually are running low on RAM before buying 16GB (this is for Windows 7).

First, use your computer! Fire it up and launch all of the apps that you generally have going. Open a few browser tabs, get your email going, etc. Try to do an average session - don't open every app on your machine. In the example below, this is my laptop that's running Outlook, IE with several tabs, Chrome with several tabs, Notepad, Windows Explorer, a couple of chat apps, Dropbox and Snag-It.

Switch to the 'Performance' tab
Click the 'Resource Monitor...' button at the bottom of the window, and it will pop up a window that looks like this.

There are 5 different sections of memory usage on the bar graph, but only 3 of them are really important to you.

First one (in grey) is hardware reserved - this is RAM that hardware uses & there's nothing you can do about this, so not important. This amount will generally be pretty low.

Third one (in orange) is 'Modified'. Also not very important because this amount is generally low, but this is RAM that's in use by low priority tasks that can be quickly released for other use.

The green section is important - this is the total amount of physical RAM that your machine is currently using (ignoring the swap file). In the graphic below, the machine is using 3GB of RAM.

The next important section is dark blue (labeled 'Standby') - this is actually not labeled well, as this is your free or available RAM. This is memory that's available for use by whatever application needs it next. In this example, there's 3GB of RAM just waiting to be used.

Finally, the light blue section labeled 'Free' - this is also kind of misleading, as this is more like wasted RAM, not free RAM. The memory in this section is the amount that Windows is just ignoring because it has no use for it. It's not being used & it's not ready to be used by anything - it's just sitting there doing nothing.

So, if someone were to show me this display & ask if they need more RAM I'd say no way, as a matter of fact you already have too much installed. I'm only actually using 3GB with another 3GB on standby and 2GB doing nothing at all. As it's running now, having 4GB in the machine would be fine, and having 6GB would give me a safety buffer. It's got 8GB installed (see the line highlighted in yellow), so I'm wasting 2GB because Windows simply has no use for it.

So do I base it on RAM usage or just disable it? I have read numerous things and it goes back and forth. The OS I am using is Windows 8.

The safest way to go is to set the size manually, with the min set at 16 megs and the max, equivalent to the amount of ram you have, so if you had 4 gigs of ram, you'd set the max at 4.000 megs.
The advantage of doing it this way, over no pagefile, is that 16 megs is so little that it forces Windows to only use your physical ram, but in an emergency, Windows would be allowed to up the minimum to the amount it needed, thus preventing a crash.
I'll post a screenshot from a Win 8 machine, in a few minutes.

The safest way to go is to set the size manually, with the min set at 16 megs and the max, equivalent to the amount of ram you have, so if you had 4 gigs of ram, you'd set the max at 4.000 megs.
The advantage of doing it this way, over no pagefile, is that 16 megs is so little that it forces Windows to only use your physical ram, but in an emergency, Windows would be allowed to up the minimum to the amount it needed, thus preventing a crash.
I'll post a screenshot from a Win 8 machine, in a few minutes.

Not necessarily. Free RAM is really wasted RAM, meaning Windows is ignoring it because it has no use for it.

Standby is the important one to look at - how much do you have on standby? That's the amount that is currently idle and waiting to be used.

That's not accurate, although the conclusion you can draw from it is sort of accurate.

Free RAM is RAM that is no longer being used in one way or another, but can't be given to another process because it needs to be zeroed out first. There exists a zeroed pool of pages of RAM that are ready to be put to use as standby.

Standby pages are pages that contain cached data. It may be a DLL that was recently unloaded, or a file that Windows expects to be loaded soon. They can be thrown out and used if a process demands it though.

So RRC06, you have about 1GB of RAM that's available for Windows to use. If that's your typical environment (in terms of the apps you're running) it probably wouldn't hurt to add a little more. If that's a relatively heavy load - if you're running more than you typically do - then you probably won't notice a difference with more RAM.

So RRC06, you have about 1GB of RAM that's available for Windows to use. If that's your typical environment (in terms of the apps you're running) it probably wouldn't hurt to add a little more. If that's a relatively heavy load - if you're running more than you typically do - then you probably won't notice a difference with more RAM.

Thanks for your help.... with 2 open DIMM slots, I think a 2 x 2 GB DDR3 kit should be enough, but unfortunately it seems like the slickest deals on RAM were last year